#include <bits/stdc++.h>

using namespace std;

#define FOR(i, a, b) for(int i = (a); i < (b); i++)
#define RFOR(i, a, b) for(int i = (a) - 1; i >= (b); i--)
#define SZ(a) int(a.size())
#define ALL(a) a.begin(), a.end()
#define PB push_back
#define MP make_pair
#define F first
#define S second

typedef long long LL;
typedef vector<int> VI;
typedef pair<int, int> PII;
typedef double db;

void solve()
{
	int n;
	LL s;
	cin >> n >> s;
	VI a(n);
	FOR (i, 0, n)
		cin >> a[i];
	multiset<LL> free(ALL(a));
	int ans = 0;
	multiset<LL> capt;
	auto it = free.upper_bound(s);
	while (it != free.end())
	{
		if (it == free.begin())
		{
			cout << -1 << '\n';
			return;
		}
		it--;
		s += *it;
		ans++;
		free.erase(it);
		it = free.upper_bound(s);
	}	
	it--;
	s -= *it;
	capt.insert(*it);
	free.erase(it);
	
	while (!free.empty())
	{
		it = free.upper_bound(s);
		if (it == free.begin())
		{
			s += 2 * *capt.rbegin();
			ans++;
			capt.erase(prev(capt.end()));
			it = free.upper_bound(s);
			assert(it != free.begin());
		}
		it--;
		s -= *it;
		capt.insert(*it);
		free.erase(it);
	}
	cout << ans << '\n';
	
}

int main()
{
	ios::sync_with_stdio(0);
	cin.tie(0);
	
	int t;
	cin >> t;
	while (t--)
		solve();
	
	return 0;
}